This invention relates to disposable diapers. More particularly, this invention relates to disposable diapers adapted to be secured in place by adhesive tabs.
Disposable diapers provide substantial advantages in convenience over conventional diapers and commonly have a generally quadrilateral configuration with straight or curvilinear longitudinal edges. Disposable diapers comprise a moisture-impermeable backing sheet and a moisture-retaining layer anchored thereto, and are conveniently secured about an infant by means of adhesive tape tabs which are affixed to the diaper along a longitudinal edge thereof, thus eliminating the need for extraneous fasteners, such as pins. In order to protect the adhesive surfaces of the tape tabs, usually a cover strip having a release surface is applied over these adhesive surfaces for subsequent removal when the diaper is about to be used. However, such tabs usually project beyond the confines of the diaper to a considerable extent and interfere with the efficient manufacture and packaging of the diaper.
In an attempt to solve the foregoing problems, U.S. Pat. No. 3,776,234 to Hoey proposes to fold the tab over on itself at the diaper's edge and to adhesively attach a portion of the folded-over tab segment to an inwardly-folded margin of the diaper backing sheet in order to keep the tab flat against the diaper and thus from interfering with the manufacturing machinery and with the subsequent folding and packaging operations. This requires that the edge of the diaper backing sheet be folded over to present an attachment surface at the front or inside face of the diaper, and a relatively involved tab design is necessary for this purpose. Also, undesirable tearing of the diaper facing fabric may result if such a tab is inadvertently adhesively attached to the facing fabric of the diaper during manufacture.
U.S. Pat. No. 3,750,669 to DeLuca shows a fastening tape provided with an adhesive end portion which extends beyond a cover strip for the tape and which is attached to a diaper inner covering or facing. However, such an adhesive end portion, when attached to a fibrous, non-woven facing fabris is likely to tear the facing fabric upon separation therefrom.
U.S. Pat. No. 3,646,937 to Gellert shows a fastening tab which is provided with a release surface permanently bonded to the inside surface of the diaper; however, such an arrangement is disadvantageous because the release surface may be placed in contact with the infant's skin when the diaper is used and also because substantial areas of the backing sheet are placed in contact with the infant's tender skin.
Additionally, for ease of application of the diaper about an infant, a relatively long free end for the adhesive tab is desirable, yet the longer the free end the more severe are the manufacturing and packaging problems.